Heading into super Tuesday, when voters in 10 states go to the polls, super PACs supporting Mitt Romney, Newt Gingrich and Rick Santorum have dumped nearly $10 million into those races. Following the money reveals that half are key battlegrounds.

According to our Super PAC Tracker, total super PAC spending topped $67.5 million as of Friday, as expenditures continued to mount in Super Tuesday states. The pro-Romney Restore Our Future has spent slightly more than $5.1 million in five of them: Georgia, Massachusetts, Ohio, Oklahoma and Tennessee. That compares to nearly $3.3 million dropped on five states by Winning Our Future, the super PAC supporting Newt Gingrich, and $1 million spent in six states by the Red White and Blue Fund, which supports Santorum.

All eyes — and a lot of the cash — are on Ohio. The three super PACs have dumped $3.8 million on the Buckeye state alone. Of that amount, Restore Our Future was responsible for $2.3 million.

Georgia, Gingrich's home state, and Tennessee are also seeing significant super PAC love, with $2 million and $1.8 million pumped into those states respectively. Though it is a populous state that's certain to be a key battleground in the fall, Virginia is getting less attention because only two of the major candidates for the GOP nomination, Romney and Ron Paul, succeeded in qualifying for the ballot.

Endorse Liberty, a super PAC supporting Paul, isn't reporting state-specific expenditures. But, the organization has disclosed spending $38,383 since Feb. 21. Nearly $31,000 of that was spent on "legal fees" with the Skadden law firm. Much of the the rest was spent on Internet advertising on sites like Facebook, Google and StumbleUpon.

The states that will be voting on March 6 are:

Alaska

Georgia

Idaho

Massachusetts

North Dakota

Ohio

Oklahoma

Tennessee

Vermont

Virginia

Below is a chart showing the presidential super PACs' spending in those states since Feb. 21, based on their reports to the Federal Election Commission: